Insomnia is a significant public health problem for older adults with substantial medical, psychological and financial ramifications. With as many as 20-30% of older adults (age =55) meeting diagnostic criteria for chronic insomnia, finding accessible, effective, and low-cost treatments is critical. Cognitive-Behavioral Therapy for Insomnia (CBT-I) is a non-pharmacological intervention that has been shown to be efficacious when tailored for older adults. Regrettably, access to this treatment is significantly limited by a lack of trained clinicians and expense. To overcome barriers to face-to-face care, use of the Internet has emerged as a feasible and effective method to provide health information and treatment. Unfortunately, the health care field has been reluctant to use technology-delivered solutions with older patients out of a concern that older adults either do not have access to or do not want to use technology. However, older adults in the U.S. are the largest growing group of Internet users, and they generally have a desire to learn new technologies. When older adults do use technology-based programs for health promotion, they rate these programs favorably. Internet-delivered CBT-I for older adults has a high likelihood of major public health impact by allowing wide- spread access to a needed intervention, increasing the convenience of obtaining care, and decreasing treatment costs among an age group with high rates of insomnia known to exacerbate other concerns (health, mood, cognition). Our research team previously developed and tested an Internet-delivered, automated intervention based on the primary tenants of CBT-I for adults under 65 (SHUTi: Sleep Healthy Using The Internet, R34MH70805 and R01MH086758). Pilot data with a subset of users aged 55-65 indicates that the Internet intervention is feasible and efficacious in this age group; however, this age group differs from the younger cohort in terms of greater dropout and smaller magnitude of improvement (although still significant). The primary goal of this grant is to conduct the first RCT of an Internet intervention tailored for older adults with insomnia (OAWI). We will recruit 309 OAWI in a 3 (Patient Education (PE) website vs. SHUTi for Older Adults vs. SHUTi-OA + Stepped Care (SC)) X 4 (Pre, Post, 6 and 12 month follow-up) design. We hypothesize that adults who receive SHUTi-OA (or SHUTi-OA+SC) will show greater improvements in sleep and daytime variables compared to those in the PE website. We also expect that SHUT-OA+SC (provision of personalized emails or phone calls to participants not completing assigned tasks) will result in greater utilization and better outcomes than SHUTi-OA without support, but at increased cost. Cost-effectiveness analyses and acceptability curves will determine the incremental benefit achieved with the additional costs. If the Internet intervention proves efficacious in a large RCT, it would yield an effective, relatively low-cost, and readily scalable insomnia solution for the fastest-growing demographic in the U.S. (older adults) who experiences the greatest rates of insomnia.